| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ho0.1 |  |-  T : ~H --> ~H | 
						
							| 2 |  | ffn |  |-  ( T : ~H --> ~H -> T Fn ~H ) | 
						
							| 3 | 1 2 | ax-mp |  |-  T Fn ~H | 
						
							| 4 |  | ax-hv0cl |  |-  0h e. ~H | 
						
							| 5 | 4 | elexi |  |-  0h e. _V | 
						
							| 6 | 5 | fconst |  |-  ( ~H X. { 0h } ) : ~H --> { 0h } | 
						
							| 7 |  | ffn |  |-  ( ( ~H X. { 0h } ) : ~H --> { 0h } -> ( ~H X. { 0h } ) Fn ~H ) | 
						
							| 8 | 6 7 | ax-mp |  |-  ( ~H X. { 0h } ) Fn ~H | 
						
							| 9 |  | eqfnfv |  |-  ( ( T Fn ~H /\ ( ~H X. { 0h } ) Fn ~H ) -> ( T = ( ~H X. { 0h } ) <-> A. x e. ~H ( T ` x ) = ( ( ~H X. { 0h } ) ` x ) ) ) | 
						
							| 10 | 3 8 9 | mp2an |  |-  ( T = ( ~H X. { 0h } ) <-> A. x e. ~H ( T ` x ) = ( ( ~H X. { 0h } ) ` x ) ) | 
						
							| 11 |  | df0op2 |  |-  0hop = ( ~H X. 0H ) | 
						
							| 12 |  | df-ch0 |  |-  0H = { 0h } | 
						
							| 13 | 12 | xpeq2i |  |-  ( ~H X. 0H ) = ( ~H X. { 0h } ) | 
						
							| 14 | 11 13 | eqtri |  |-  0hop = ( ~H X. { 0h } ) | 
						
							| 15 | 14 | eqeq2i |  |-  ( T = 0hop <-> T = ( ~H X. { 0h } ) ) | 
						
							| 16 | 1 | ffvelcdmi |  |-  ( x e. ~H -> ( T ` x ) e. ~H ) | 
						
							| 17 |  | hial0 |  |-  ( ( T ` x ) e. ~H -> ( A. y e. ~H ( ( T ` x ) .ih y ) = 0 <-> ( T ` x ) = 0h ) ) | 
						
							| 18 | 16 17 | syl |  |-  ( x e. ~H -> ( A. y e. ~H ( ( T ` x ) .ih y ) = 0 <-> ( T ` x ) = 0h ) ) | 
						
							| 19 | 5 | fvconst2 |  |-  ( x e. ~H -> ( ( ~H X. { 0h } ) ` x ) = 0h ) | 
						
							| 20 | 19 | eqeq2d |  |-  ( x e. ~H -> ( ( T ` x ) = ( ( ~H X. { 0h } ) ` x ) <-> ( T ` x ) = 0h ) ) | 
						
							| 21 | 18 20 | bitr4d |  |-  ( x e. ~H -> ( A. y e. ~H ( ( T ` x ) .ih y ) = 0 <-> ( T ` x ) = ( ( ~H X. { 0h } ) ` x ) ) ) | 
						
							| 22 | 21 | ralbiia |  |-  ( A. x e. ~H A. y e. ~H ( ( T ` x ) .ih y ) = 0 <-> A. x e. ~H ( T ` x ) = ( ( ~H X. { 0h } ) ` x ) ) | 
						
							| 23 | 10 15 22 | 3bitr4ri |  |-  ( A. x e. ~H A. y e. ~H ( ( T ` x ) .ih y ) = 0 <-> T = 0hop ) |